Report of the meeting of the SC-04-03 Working Group on loudspeaker modeling and measurement of the SC-04 Subcommittee on Acoustics, held in New York, NY, USA, 2017-10-20

The agenda and the report of the previous meeting, held in Berlin, 2017-05-22, were approved as written.

Projects assigned to this group but not mentioned here had no action requested or required - see www.aes.org/standards/meetings/project-status.cfm for details.

Open projects

AES2-R Review of AES2-2012: AES standard for acoustics - Methods of measuring and specifying the performance of loudspeakers for professional applications - Drive units
Review is required in 2017. Since the revision currently in progress is not yet ready it was agreed that AES2-1012 will be reaffirmed.

Comments on the revision.

Power rating
- should be modified.
- complex impedance should be included in a more detail power analysis.
- test signals should be reviewed, including Crest Factor
- “Maximum Input Voltage, MIV will be updated to reflect the nature of the test, to find the point of non-linear response output so will be edited to “Maximum Useful Voltage, MUV”.
– There are many more attributes to be considered for the next AES2 revision.

AES-1id-R
This document is due for formal review in 2017, with reaffirmation the most obvious outcome. David Murphy provided an overview of based on PWT analysis that can be added as an annex. A draft is posted to the reflector.
Comments are welcome.

AES-X168 Characterization of loudspeaker systems;
Revised scope:
This document defines a set of characteristics of loudspeaker systems for inclusion in manufacturers’ specification documents, and identifies the relevant methods of measurement. The document considers loudspeaker systems for professional applications. They may be combinations of active and passive sub-systems. It is intended for users and designers of loudspeaker system installations.

Status:
David Murphy has formed a first rough draft posted to the reflector.

Discussion:
It was agreed that the standard should be organized as a wholistic approach and consider all systems as closed box, from mains power input to acoustic power output. Passive systems would include options to use different power amplifiers however the standard should address the test & measurement procedure.

Target: Draft fall 2018

AES-X223: Loudspeaker Driver Correlation Chamber: Information Document:
Status:
The latest draft was posted to the TCLH web site in September.

Comments:
It was noted that the annotation for figure A3 may be somewhat ambiguous & needs review.
It was also noted that absorption material should be addressed with some form of specification, even if calibration negates minor differences.

Goal:
Updated draft November 2017.
Release May 2018 (or earlier).

AES-X241 AES Standard for Acoustics - End of Line Testing for Production Loudspeaker Drivers
Richard Stroud has updated the latest draft with input from the industry.

Discussion:
It would be very useful to include side documents or an addendum as templates for different types of drivers.
Dr. Angelo Farina is processing data from a survey soliciting ideas on what is important in end of line driver testing. A report may be available November 2017. When the report is available test prioritization can be considered.

Intent Target: Release 2018

Liaisons:

Interaction with TCLH & IEC continues & will become more interactive in the coming months.

New Projects

See above.

New Business

There was no new business.

The next meeting will be scheduled in conjunction with the AES 144th Convention in Milan, Italy, 2018-05.

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